LN in WPS Spreadsheet: Use Natural Logarithms and Invert Exponential Models

• Introduced: documented by 2019-06-10 in the official WPS lesson; original introduction is not established.
• Availability: WPS Office for Windows Personal; no numeric release is stated. This is documentation evidence, not an installed-build guarantee.
• Scope: exact supported builds remain unverified. The Windows lesson does not establish equivalent availability in other WPS clients.
• Checked: October 14, 2026 against function-specific documentation. Examples were independently calculated; no native WPS test was performed.

=LN(number)

number must be positive for the real-valued logarithm described by the source. A value between zero and one is valid and has a negative logarithm. Zero and negative inputs lie outside this documented real domain; the short lesson does not specify their exact current native error labels.

LN is the inverse of EXP, rather than a base-ten logarithm. Use LOG10 for base ten or LOG for an explicit base. English function names are used in these examples.

Put numeric 0.25, 0.5, 1, 2, 4 in A2:A6. Fill down:

=LN(A2)

Expected values are approximately -1.386294361, -0.693147181, 0, 0.693147181 and 1.386294361. The two reciprocal pairs have opposite logarithms, and one maps to zero.

A negative logarithm does not mean the original input was negative. For example, 0.25 is positive but lies below one. Check that distinction before rejecting a negative output as a data error.

Two measurements in the same unit have values 40 and 10:

=LN(40/10)
=LN(40)-LN(10)

Both have independently expected result approximately 1.386294361. The ratio is dimensionless, and the logarithm describes their multiplicative relationship.

The subtraction identity requires positive inputs. It is not permission to take logarithms of negative values just because their quotient happens to be positive. Keep the individual domain conditions when transforming an expression.

For positive values 4 and 16:

=EXP((LN(4)+LN(16))/2)

Expected result: 8. The logarithms are averaged, then EXP returns to the original scale. The arithmetic mean is 10, so the choice of summary changes the answer.

For three positive values 2, 8, 32, averaging their three natural logarithms and exponentiating also gives 8. This represents the cube root of their product. It is not a general replacement for an arithmetic mean; use it when a multiplicative interpretation is intended.

Suppose the chosen model is Q(t)=100*EXP(-0.3*t) and the target is 50. Dividing by 100 and taking natural logarithms gives:

=LN(2)/0.3

Independent expected time: approximately 2.310490602 units. Substituting that unrounded result into the original model gives expected quantity 50.

The coefficient 0.3 is per the same time unit used for t. This is a mathematical consequence of the specified model, not evidence that a real process has that half-life. A different target fraction or rate needs a recalculated expression.

=LN(EXP(2)) has independently expected result 2, while =EXP(LN(9)) has expected result 9. Use small finite controls to separate an incorrect formula from an unsupported extreme-magnitude case.

For an editable source in C2, inspect positivity before interpreting its logarithm. Replacing an invalid input with an arbitrary tiny positive value changes the calculation and should never be an invisible cleanup step.

The WPS lesson establishes the natural base, positive-real domain and inverse relationship. It does not certify a complete text, Boolean, zero, negative or precision-error matrix for current releases. Those exact native outcomes remain open.

If the expected scale is wrong, check whether the question calls for natural or base-ten logarithms. A cell displayed as zero can contain a small positive value, while a stored zero is outside LN’s stated domain. Preserve source precision and inspect the underlying value rather than relying solely on rounded display text.

• WPS Academy: LN lesson, 2019-06-10 (Chinese; Windows Personal scope).
• Editorial testing standards.

The cited WPS product lesson was read directly. Worked outputs are independent expectations, not captured native results or proof of support across all current WPS clients.